from car import ElectricCar

tesla = ElectricCar('Tesla', 2020, 'model s')

tesla.showInfo()
# ElectricCar: Tesla, 2020, model s.

tesla.showBatterySize()
# Current battery size is: 0.

tesla.updateBatterySize(-40)
# input number must greater than 0

curSize = tesla.updateBatterySize(60)
print (curSize)
# 60

curSize = tesla.incrementBattery(3)
print (curSize)
# 63